Disc derangements of the temporomandibular joint. A tissue-based characterization and implications for surgical treatment.

Disc-related derangement of the temporomandibular joint is common and epidemiological research has found that about 20% of the population may be affected. Although very few of these people have the more prominent symptoms, recent data indicate that the numbers who need treatment is increasing. The two clinical variants of disc derangement, reciprocal clicking and closed lock, have long been recognized, but the association between them and their aetiology and pathogenesis is still unclear. As a consequence, there is still uncertainty on how to treat the conditions, and this is even more evident when surgery is involved. This paper describes new tissue research related to disc derangement. A simplified scheme is presented and implications for surgical treatment are discussed.